A simple JS code snippet that gets the current time and date and displays it in an HTML textfield while updating every second.

time_and_date.js

var x = setInterval(function() {
  // get the date first
  var myDate = new Date();
  var myDay = myDate.getDay();
  // then create a list of days of the week
  var weekday = ['Sunday', 'Monday', 'Tuesday',
      'Wednesday', 'Thursday', 'Friday', 'Saturday'
  ];
  // then make strings that add "0" in front of 1-digit hrs/mins
  var dayNum = String(myDate.getDate()).padStart(2, '0');
  var monthNum = String(myDate.getMonth() + 1).padStart(2, '0');
  var yearFullNum = myDate.getFullYear();
  // then the same with time
  var hours = String(myDate.getHours()).padStart(2, '0');
  var minutes = String(myDate.getMinutes()).padStart(2, '0');
  var seconds = String(myDate.getSeconds()).padStart(2, '0');
  // compile two strings
  var dateString = weekday[myDay] + ", " + dayNum + "." + monthNum + "." + yearFullNum
  var timeString = hours + " : " + minutes + " : " + seconds
  // and put the string into the "titletext" HTML element of your website
  document.getElementById("titletext").innerHTML = (dateString + "<br>" + timeString);
}, 1000);